The invention is related to the field of photonic crystal holey fibers, and in particular to obtaining zero group-velocity modes in photonic crystal holey fibers.
Photonic crystal holey fibers have been of great interest for a variety of different applications, mainly using silica or polymers with low index contrasts (1.5; 1). Researchers have also studied photonic crystal fiber-like geometries with high index contrast materials (eg. Si or GaAs, index 3.4) and shown that they support interesting zero group-velocity modes, but such modes have not been described for fibers made of easily drawable materials.
Holey fibers, formed by a lattice of air holes in the fiber cross section, are best known for supporting “finger-like” band gaps opening towards the high-frequency regime, which can open even for arbitrarily low index contrasts. However, these gaps close before reaching a zero propagation constant β, and the guided modes that they support have all been found to have nonzero group-velocity.